Traditional skateboard truck assemblies accomplish the action of turning when the rider shifts his weight on the skateboard deck from neutral to either side of the skateboard's longitudinal axis.
Consistent with FIG. 1 a complete skateboard assembly consists of two skateboard trucks with four attached wheels that are attached to a skateboard deck. Each skateboard truck comprises a baseplate assembly, which is attached to the deck, and a hanger assembly on which the wheels are hung.
As a rider leans the skateboard deck from side to side, the axle integral to the skateboard truck hanger assembly is forced to stay parallel to the ground as long as the weight of the rider forces the wheels to remain in contact with ground. Rotation of the skateboard deck around an axis parallel to the longitudinal centerline of the skateboard deck causes the skateboard truck hanger assemblies to rotate—while staying parallel to the ground—about other axes, resulting in a turning action transmitted through the skateboard truck assemblies.
Furthermore, when the deck of a typical skateboard is rotated, it causes the hanger assembly to rotate about an axis between the center of the extreme end of the pivot and a point in the center of the hanger aperture coincident with the longitudinal centerline of the kingpin. This causes fore and aft movement of the hanger and the wheels attached to it relative to the neutral position of the trucks when the deck is evenly weighted and parallel to the ground. As the rider angles the deck, the wheels proximate to the weighted side that is angled toward the ground move toward the middle of the skateboard deck, and the wheels on the opposite side from the weighted edge of the deck move away from the middle of the skateboard deck toward the ends of the skateboard deck. The result is that the trucks allow the rider to turn the skateboard by converting the force created by the leaning of the skateboard deck into a controlled turning action. The turning action is accomplished by the fore and aft movement of the wheels attached to the skateboard trucks as they rotate on the kingpin which is oriented at an angle less than 90 degrees to the ground plane (FIG. 8).